This article describes the Ounce of Prevention Fund's journey to institutionalize doula services in the state of Illinois. The Ounce's doulas help strengthen the new relationship between mother and child by working with the mother to help her better understand and anticipate the progression of the third trimester of pregnancy, the child-birthing process, and her baby's early development. The growth of doula programs in Illinois from 3 to 18 in less than 10 years is, at heart, a financing story. The Ounce of Prevention Fund undertook replication of pilot doula programs through sustained, ongoing, and stable public funding streams. The Ounce sought to weave the doula model into larger, pre-existing government programs. Institutionalization has become part of the Fund's organizational theory of change, and its method of replicating programs. The authors describe four principles that have been key to success: (1) relationships matter; (2) advocacy matters; (3) public-private partnerships and funding matter; and (4) mutual interest and goals matter.